Authentication reader for motor vehicle opening element

Abstract

Disclosed is an authentication reader intended to be installed on a motor vehicle opening element, the reader including a microcontroller, at least one transmitter, at least one matching circuit and a single antenna, called “primary” antenna, characterized by a working frequency. The matching circuit includes switching element able to switch the matching circuit between a first mode, in which the matching circuit makes it possible to match the primary antenna to a secondary antenna of an authentication device whose resonant frequency is lower than the working frequency, and a second mode, in which the matching circuit makes it possible to match the primary antenna to a secondary antenna of an authentication device whose resonant frequency is higher than the working frequency.

The invention claimed is: 
     
       1. An authentication reader for a motor vehicle opening element, said authentication reader comprising:
 a microcontroller; 
 at least one transmitter; 
 a single primary antenna having a working frequency; and 
 at least one matching circuit comprising
 a switch system configured to switch said at least one matching circuit between a first mode in which the at least one matching circuit permits the primary antenna to match a secondary antenna of an authentication device having a resonant frequency lower than the working frequency, and a second mode in which the at least one matching circuit permits the primary antenna to match a secondary antenna of another authentication device having a resonant frequency higher than the working frequency, the switch system comprising a first switch and a second switch, 
 a branch connected to: (i) the at least one transmitter via an input terminal, and (ii) the at least one primary antenna via an output terminal, said branch comprising the first switch, a first capacitor, and the second switch, the first switch being connected to the input terminal and being configured to switch between a first connection point for connection to the first capacitor and a second connection point for connection to the ground, 
 a second capacitor, and 
 a third capacitor connected to the ground, 
 
 wherein the second switch is connected to the output terminal and is configured to switch between a first connection point situated at the center tap between the first capacitor and the second capacitor, and a second connection point situated at the center tap between the second capacitor and the third capacitor, and 
 the single primary antenna is connected between the output terminal and the ground. 
 
     
     
       2. The authentication reader according to  claim 1 , wherein the branch comprises
 an inductor connected between the input terminal and the first switch, 
 a fourth capacitor connected between the first connection point and the second connection point of the first switch, and 
 a fifth capacitor connected between the second connection point of the first switch and the ground. 
 
     
     
       3. A motor vehicle, comprising:
 at least one opening element, said at least one opening element comprising the authentication reader as claimed in  claim 1 . 
 
     
     
       4. A motor vehicle, comprising:
 at least one opening element, said at least one opening element comprising the authentication reader as claimed in  claim 2 . 
 
     
     
       5. An authentication system for locking or unlocking the at least one opening element of the motor vehicle as claimed in  claim 3 , said authentication system comprising:
 at least one authentication device; and 
 the motor vehicle. 
 
     
     
       6. An authentication system for locking or unlocking the at least one opening element of the motor vehicle as claimed in  claim 4 , said authentication system comprising:
 at least one authentication device; and 
 the motor vehicle.